The present disclosure relates to downhole tools used in the oil and gas industry and, more particularly, to degradable downhole tools comprising a doped alloy that at least partially degrades in the presence of fresh water having a salinity of less than about 1000 parts per million (ppm).
In the oil and gas industry, a wide variety of downhole tools are used within a wellbore in connection with producing hydrocarbons or reworking a well that extends into a hydrocarbon producing subterranean formation. For examples, some downhole tools, such as fracturing plugs (i.e., “frac” plugs), bridge plugs, and packers, may be used to seal a component against casing along a wellbore wall or to isolate one pressure zone of the formation from another.
After the production or reworking operation is complete, the downhole tool must be removed from the wellbore, such as to allow for production or further operations to proceed without being hindered by the presence of the downhole tool. Removal of the downhole tool(s) is traditionally accomplished by complex retrieval operations involving milling or drilling the downhole tool for mechanical retrieval. In order to facilitate such operations, downhole tools have traditionally been composed of drillable metal materials, such as cast iron, brass, or aluminum. These operations can be costly and time consuming, as they involve introducing a tool string (e.g., a mechanical connection to the surface) into the wellbore, milling or drilling out the downhole tool (e.g., breaking a seal), and mechanically retrieving the downhole tool or pieces thereof from the wellbore to bring to the surface.